Vecna

Vecna, born Henry Creel and later revealed as Subject 001, is a fictional character created by the Duffer Brothers for the Netflix television series Stranger Things. Portrayed by Jamie Campbell Bower and Raphael Luce as Henry Creel / Subject 001, the character made his debut in the fourth season, as a diabolic being from the Upside Down that haunts his victims with horrifying visions of their past traumas before killing them in a very brutal way. As the fourth season progresses, he is ultimately to be revealed the ruler of the Upside Down as well as the mastermind behind all of the events of the series that have terrorized the town of Hawkins, beginning with the disappearance of Will Byers.